考虑交通区位的物流配送中心选址模型及求解

从交通运输系统的角度出发,物流配送中心选址在考虑物流规划部门与客户之间利益分配问题的基础上。还应该考虑到交通区位优势给物流配送中心运营带来的便利性。在已有双层规划模型的基础上进行改进,通过在模型中设立相关参数来描述交通区位产生的影响。建立了考虑交通区位的物流配送中心选址双层规划模型,同时还考虑到竞争的存在。笔者设计了基于遗传算法的模型求解算法,最后通过一算例来对比验证模型及其算法的可行性。在物流配送中心选址时利用交通区位优势能大大提高其运营效率及效益。     

关于打造先进公路文化的思考

党的十六大报告中指出:"全面建设小康社会,必须大力发展社会主义文化,建设社会主义精神文明。"作为公路行业,就是要打造社会主义先进公路文化。文章试通过对先进公路文化的内涵、特征和作用的分析探讨,进而提出打造先进公路文化,推进公路事业跨越式发展的建议。     

Estimating the impact of incidents on urban controlled-access highways: an empirical analysis

An empirical analysis is developed that quantifies the impact of different types of traffic incidents on the speed and maximum flow averages of vehicles on a controlled-access highway. The incident types considered include damage to highway infrastructure, vehicle rollover, crashes (into stationary objects), collisions (with moving vehicles), rain, fog, vehicle breakdowns, pedestrians on roadway, etc. Using real-world data from Chile’s most heavily used urban motorway/freeway, estimates of incident impacts on speed are generated using a multiple linear regression model incorporating instrumental variables to correct for endogeneity. Flow results are then generated using the fundamental traffic equation relating speed, flow and density. A ranking of the impacts on highway traffic of the different incident types based on incident frequency as well as impact size demonstrates that for the real case studied, the incidents with the greatest cumulative effect are (in order of magnitude) vehicle breakdown, collisions and rain.     

城市单向交通系统的应用研究--以长春市为例

在保持原有道路交通路网的条件下,单向交通是改善大中城市交通堵塞状况的经济而有效的方法之一.通过对单向交通及长春市交通路网情况分析,阐明长春市采用单向交通的优势、存在问题并提出完善长春市单向交通系统的建议.     

交通拥堵现象背后的社会问题

分析了北京交通拥堵的症结,论述了应遵循的交通理念,提出了改善交通拥堵的建议.     

北京交通拥堵症结分析

分析了北京城市交通拥堵的原因,提出了解决这一问题的思路.     

网络拓扑结构对交通流量分布特性的影响分析

分析城市交通网络特性,建立双层城市交通网络模型,其中下层为道路网络,上层为出行网络.以节点平均负荷、拥堵节点、网络负荷标准差、基尼系数为主要指标,研究居民出行网络拓扑结构变化过程中道路网络流量分布的变化情况.研究结果显示,出行网络拓扑结构对交通量分布有较大影响,且存在最优出行网络结构,使城市交通状况达到最佳.     

Port traffic risks – A study of accidents in Hong Kong waters

This paper investigates port traffic risk issues by discussing historic accidents in Hong Kong port. A total of 2012 marine accidents with 94 deaths were reported in Hong Kong waters in year 2001–2005, while 660,427 oceanic ships visited the port. A negative binomial regression model is used to analyze the record of dataset. It is found that port traffic risks are of certain pattern and collision accidents are the most popular incidents when port traffic is heavy. Passenger-type vessels have higher potential for injuries during accidents. The findings have identified statistically significant factors for improvements in managing port traffic risks.     

基于SSR和ADS-B混合监视的机载编队防撞系统设计

由于设备性能的限制,民航飞机目前使用的机载防撞系统TCASⅡ不能适用于编队飞 行防撞。为了解决飞机编队飞行防撞以及与民航飞机TCASⅡ兼容的问题,给出了一种基 于二次雷达(SSR)和ADS-B混合监视的机载编队防撞系统的设计方案。该方案采用了TCAS主动 监视和被动监 视相结合的方法,利用唯一的24位S模式地址来识别和归类目标飞机,将TCAS的监视数据和A DS-B的监视数据进行数据融合来完成对目标飞机的监视和跟踪。通过将大型编队划分为多个 编队单元的方法,由长机负责保持各个编队单元之间的安全间距。采用收发器将长机产生的 位置保持和碰撞避免的操纵指令通过高频数据链路传送给各个编队单元,各个编队成员按照 操纵指令调整自己飞机的位置,完成对整个编队的位置保持和碰撞避免的集中控制和分散执 行。该方案可以为机载编队防撞系统的设计和实现提供参考和帮助。     

An analysis of highway work zone safety practices in Pakistan

Highway Work Zones (HWZs) present a major hazard for road users, construction workers and equipment, and significantly contribute to occurrence of road crashes worldwide. The present study focuses on analysing the current state of safety measures at HWZs in Pakistan. A more direct approach is adopted by comparing safety measures at randomly selected HWZs in Pakistan with well-established safety procedures in Manual on Uniform Traffic Control Devices (MUTCD). HWZ safety measures such as traffic signs, markings, safety measures for pedestrians, workers and construction machinery, police enforcement, speed control measures, provision of advance warning area, buffer spaces, transition areas, and tapers for eight different HWZs were studied and compared with MUTCD standards. The results revealed that majority of the HWZs in Pakistan do not conform to any standard layout especially for safety and speed control measures. An enhanced need for special efforts towards improving safety at HWZs in Pakistan is highlighted.